production gone sour: pesticide exposure and …...production gone sour: pesticide exposure and...
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Production Gone Sour: Pesticide Exposure and Cranberry Bogs in Plymouth County, MA
Plymouth County, MA is home to a high propor-
tion of the state’s cranberry bogs and the subject
of this analysis. Cranberry bogs are both aquatic
and terrestrial in nature and thus subject to high
levels of unwanted pests and plant diseases. For
that reason, the seasonal application of pesticides,
herbicides, and fungicides is common on cranber-
ry bogs. There are several pesticides commonly
utilized on cranberry bogs, the most common of
which is Chlorothalonil. This fungicide travels
mostly through soil and has been categorized as a
likely human carcinogen. According to studies
conducted by the USGS, application of Chlorotha-
lonil in Plymouth County has increased from
158.8 kg in 1990 to 336.7 kg in 2005. Perhaps in
ignorance of this fact, Plymouth County residents
continue to settle in close proximity to cranberry
bogs.
Overview
Admittedly, this model presents a highly simplistic
version of the spread of pesticides. This model as-
sumes exposure risk based solely on proximity to
cranberry bog and ignores the many ecological
forces that contribute the spread of pesticides. Alt-
hough much of the research on Chlorothalonil
claims that it does not travel well in air and water,
it is inevitable that some pesticide is diffused in
that matter. This would significantly increase the
range of exposure, and thus the number of Plym-
outh County residents exposed to cranberry-bog
related pesticides and fungicides. Also, there is un-
certainty in the land use data for 1990 and 2005.
Land use for both years was determined from aeri-
al photographs, an oft inaccurate technique. For a
variety of environmental and financial reasons,
cranberry bogs are often left abandoned or fallow
for extended periods of time. Fallow fields could
imply no pesticide use. From this dataset, there is
no way to determine which bogs are in use and
which are not. Also, the dramatic decrease in
“Low-Density Residential” land use is questiona-
ble, considering the seemingly small decrease in
area pictured below. Perhaps the aerial data col-
lected in 1990 overestimated the number of low-
density residences, making the change between
1990 and 2005 appear more dramatic than reality.
Finally, this model assumes that all cranberry bogs
use the same types of pesticides in the same vol-
ume – and that all cranberry bogs even utilize pes-
ticides.
Massachusetts State Plane Projection
Town Boundaries: MassGIS, February 2014
Hydrography: MassGIS, March 2010
Land Use (1990): MassGIS, Massachusetts Executive Office of En-
vironmental Affairs, January 2002
Land Use (2005): MassGIS, June 2009
Pesticide Usage: USGS Pesticide National Synthesis Project, 1991
& 2006
In terms of land use, both “Low-Density Residen-
tial” and “Cranberry Bogs” appear to have de-
creased in hectares between 1990 and 2005. In
terms of pesticide exposure, the number of resi-
dences within “Highest” and “Higher” exposure
appear to have decreased between 1990 and 2005,
whereas the number of residences in “High” and
“Least High” appear to have increased. Keep in
mind that use of Chlorothalonil increased over
this same time period. The decreasing hectares
categorized as low-density residential could imply
that Plymouth County residents are relocating
away from this area of high cranberry production.
Or, as implied by the decreasing number of resi-
dences within “Highest” and “Higher” exposure,
residents could be moving further away from the
cranberry bogs but still within the region of inter-
est to areas of “High” and “Least High” exposure.
Whether this observed movement is related to in-
creasing use of pesticides such as Chlorothalonil
is not determined in this analysis.
Works Cited
Cranberry Bogs and Rural Residential Settlement
Methods
The purpose of this model is to analyze the rela-
tionship between cranberry bogs and subsequent
pesticide exposure of surrounding populations.
Was the increased application of Chlorothalonil in
response to land use changes occurring over the
same time period? Which portions of the popula-
tion were most susceptible to these increases in
pesticide use? First, an analysis was performed to
determine changes in cranberry bog and residential
settlement area between 1990 and 2005. Plymouth
County is rural and thus low in population density,
so “Low-Density Residential/ housing on ½ - 1
acre plots” was chosen to represent population set-
tlement in the region of interest. Second, a raster
algebra analysis was performed to determine loca-
tions in the area of interest with highest risk of ex-
posure to pesticides from cranberry bogs. Prior to
this step, a Euclidean distance of 500m was per-
formed on both cranberry and low-density residen-
tial land uses for 1990 and 2005. Areas categorized
as “highest risk” have both the highest number low
-density residences and are located closest to cran-
berry bog locations.
Discussion
Findings
Rachel L. Hoh
NUTR 231, May 2016
Population at Risk for Pesticide Exposure in Plymouth County,
1990
Population at Risk for Pesticide Exposure in Plymouth County,
2005
Total Low-Density Residential Land Use, 1990
& 2005
Total Cranberry Bog Land Use, 1990 & 2005
Land Use Changes in Plymouth County, 1990 & 2005 Population at Risk of Pesticide Exposure, 1990 & 2005 Percentage of At-Risk Population at Specific Risk Levels, 1990
& 2005